#!/bin/bash

#if 选择的几种使用方式

if [ a = a  ]
then
  echo "a=a"
fi


if [ a = b ]
then
  echo "a=b"
else
  echo "a!=b"
fi


if [ a = b  ];
then
  echo "a=b"
elif [ a = c ];
then

  echo "a=c"
elif [ c = c ];
then
  echo " c=c "
else
  echo "没有正确的表达式运行"

fi
